Aspects of the present invention are directed to a tray holder and, more particularly, a holder for Joint Electron Devices Engineering Council (JEDEC) tray manipulation.
Integrated circuit (IC) manufacturing processes use trays as the transport media to protect sensitive electronic devices from mechanical and electrostatic damage that may occur in typical manufacturing of IC devices. These processes take stacks of trays containing IC devices as input and output and require manual handling of stacks of trays between process steps and in and out of in-process storage.
Common methods of handling stacks of trays containing IC devices presently include the use of individual or loose trays where the operator grabs stacks of 6-14 trays without any device to restrain the trays in the stack to transport the same from station to station. This technique runs the risk of operator error where trays come unstacked. Stainless steel baskets may be used where the operator stacks trays with IC devices in a stainless steel basket to transport the same from station to station. Metal baskets are typically required to withstand the thermal environment of some process steps, making them too heavy for routine tray stack handling. Extruded C-clips cut to length to bind two trays together have been used.
An additional system involves the use of banding straps where the operator bands a stack of trays together using a secure bundle of trays to transport the IC devices from station to station. The use of a band which is buckled about the trays is not user friendly, however, in preparing the bundle or unbundling for single tray access. In particular, straps are often made of a plastic material and they may be applied at a remote strapping machine to tray stacks between each process operation (i.e., many times during production flow). The straps are then cut and removed at each operation. As such, a number of manipulations associated with strapping operations may be significant, the use of plastics and the inability to reuse the straps is ecologically unsustainable and tray contamination and scratch damage due to the strapping leads to tray deterioration.
In view of these issues, a further system for securing trays in a stack was proposed in U.S. Pat. No. 5,421,455, in which a clip attaches individual trays in a stack, the trays being formed for nesting and with end tabs located on the opposite ends of the trays. According to the '455 patent, the clip included a platform having a front and a rear surface and a leading and trailing edge, a plurality of spaced rails positioned parallel with each other positioned on the rear surface of the platform, the rails having a generally T-shape in cross-section, an end stop projecting from the trailing edge of the platform in a rearward direction for limiting the movement of the platform across the end of the stack of trays and latch means. The latch means were formed on the platform for locking the platform onto the end of a stack of trays and include a stop projecting in a rearward direction, biasing means to normally position the stop in a position projecting rearward from the rear surface of the platform and actuating means for moving the stop against said biasing means to move the stop from the rearward projecting position to a position in the plane of said rear surface.
Since the actuating means are operable in a manner that is separate from the movement of the platform relative to the stack of trays, however, the connection of the clip to the stack of trays and the disconnection of the clip involves a two-step process whereby the user manipulates the platform and the actuating means separately and at the same time. That is, in order for the clip to be connected to a stack of trays, it is necessary for the user to move the platform along the tray ends and, at the same time, to pull the actuating means such that the stop does not project rearwardly. By contrast, in order for the clip to be disconnected, the actuating means must be pulled again such that the stop does not project rearwardly and such that the platform movement is permitted. These operations are unnecessarily complicated, time consuming and expensive.